STORM-DERIVED BAR/SILL DYNAMICS IN A DREDGED CHANNEL

Sean O'Neil, Keith W. Bedford, David P. Podber

Abstract


The development of sediment bars and sills due to storm-induced flow events in a dredged Great Lakes tributary is studied. The hydrodynamics associated with long-waves from the lake, create flow reversals at the river mouth, and storm runoff produces large sediment loads delivered to the lake. A laterally-averaged numerical model, including a turbulence closure sub-model, is used to simulate the hydrodnamics. A simple sediment settling, resuspension and transport model is coupled to the hydrodynamic model. Model runs are made for flow and temperature conditions which would be typical of the region during the spring season. Runs are made with and without the sediment settling velocity term, which effectively represents the modeling of two grain sizes; clay particles which have extremely small settling velocities and tend to floe together producing neutrally buoyant particles, and silt sizes which have finite settling velocities.

Keywords


channel; dredged channel; sill dynamics; bar dynamics

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